Here is what I use:
FTP uploader:
This is not exacly what you are asking, but use scp it's more secure! It's command line driven, but once you figure it out it's SOOOOO natural and scriptable! (If something is not scriptable I don't want to hear about it!). I use it to transfer my files across windows, solaris, gentoo and redhat (I have a different distro on every system

)
HTML editor:
I use vim and stylesheets. This way I just write the contents and let the style sheets take care of the rest. Very simple. If you really want a WYSIWYG html program, get NVU (
www.nvu.com) It's very good and no reason to get wine setup.
Peer to peer file sharing:
I use mldonkey and just it's standard web interface. It also has a nice (text-only) interface which is convinient if you want to log in remotely and work on your filesharing.
Professional image editing:
Gimp
CD burner:
I've only done this on the command line to burn iso's, but I don't this it is a good way so I'm not going to mention anything here. I looked at the previous poster's K3B suggestion and it looks very good. However I don't use KDE or GNOME (just xfce) and I really don't want these huge libs just to run a CD burner.
NOTE TO OTHERS: Can anyone suggest a nice gui cd burning software which will handle mp3 --> audio, data, and iso's? I don't want it to be havy KDE or gnome based. Some nice gtk2 gui would be nice.
Media streamer:
mplayer hands down! Best tool on my box. I use it to watch ALL formats, DVD's, and encode movies. NOTE there are a TON of usefull use flags for this! The ones I remember right now are (these are for pentium4, some of these change if you have an AMD):
alsa dvd quicktime xvid mpeg sse sse2 mmx mmxext win32codecs encode
I would also add DVD burning:
This is hands down done best by DVDshrink which is only available on windows (damn it). So you have to wine this one! But NOTHING else compares!